This invention relates to a safety device for use with a machine of the type having a main drive which may be activated to move a ram with a high force against a workpiece.
Machines often employ high forces for the purposes of forming or cutting metal. At the same time, the metal forming parts often move at high speeds compared to human reflexes. As an operator is attempting to use such a machine quickly and efficiently, there is a considerable possibility of injuring his fingers.
Many safety devices have been developed to minimize the possibility for such injury, and they are as varied as the different types of machines to which they apply. The present device grew out of the use of and is particularly applicable to a type of machine having a movable ram which is driven suddenly and with great force against a workpiece on a fixed ram. A safety guard for such a machine, along with a general background discussion of safety devices, can be found in the U.S. Pat. No. 4,060,160 to Lieber. In that safety device, for example the approach is to establish a "gate" which might detect the finger of an operator in the work area and stop or reverse the ram upon such detection.